Phoenix area weather close to 100 degrees

Today is likely to be the first day of the annual march through the misery of a Valley summer.

The National Weather Service is forecasting that sometime this afternoon, the temperature will hit triple digits at Phoenix Sky Harbor International Airport, where the official temperature is recorded.

The good news is that the first 100-degree day is late. Since 1979, the first 100-degree day of the year is, on average, May 2.

This first real heat wave of the season is going to be brief. The forecast high on Monday is back in the low 80s.

The question, of course, is whether a late start to scorching temperatures means a cooler summer to follow. The answer is yes. And no.

Weather Service data show that a late first 100-degree day means there will probably be fewer of them because the "heat season" is shorter.

But the rate at which they come - or percentage of days to hit 100 between now and the end of September - will likely remain the same.